285/30R20
285/30R20 ships as an OEM size on the Chevrolet Camaro. At 26.73″ diameter with a 3.37″ sidewall (30% of section width), this size turns 754 revolutions per mile.
About 285/30R20
Factory fitments for 285/30R20 include the Chevrolet Camaro — meaning replacement tires in this size see steady demand and broad brand availability. At 26.73″ overall diameter, 285/30R20 turns 754 revolutions per mile, which is the reference point the factory speedometer and odometer were calibrated against. The 30% aspect ratio gives it an ultra-low-profile sidewall tuned for maximum steering precision — at the cost of ride comfort and rim protection. The 20″ rim pairing is typical for luxury SUV and performance-oriented platforms, so compatible wheels are easy to source new or used. Going one step shorter to 275/30R20 drops diameter by 0.88%, which stays within the ±3% fitment safe zone for most vehicles. If you are shopping for a direct replacement, any tire within roughly ±0.7″ of the 26.73″ stock diameter (about ±2% in percentage terms) will keep ABS, TPMS, and odometer readings inside the vehicle's designed tolerance.
Compare with another size
275/65R18 or "33" for inch aliases285/30R20
- Diameter
- 26.73″ / 679mm
- Section Width
- 11.22″
- Sidewall
- 3.37″ / 85.5mm
- Circumference
- 83.98″
- Revs/Mile
- 754
275/30R20
- Diameter
- 26.5″ / 673mm
- Section Width
- 10.83″
- Sidewall
- 3.25″ / 82.5mm
- Circumference
- 83.24″
- Revs/Mile
- 761
Speedometer & Diameter Impact
At an indicated 60 mph, your actual speed is 59.47 mph (95.71 km/h). Your speedometer reads 0.88% high versus actual speed.